Our present invention relates to a method of packaging plastic bags held in stacks by means of wire brackets, particularly bags for automated machines, into a transport container or box, especially a cardboard box, and for removal of the bag package from the transport box.
In a continuous production of plastic bags, a multiplicity of bags are collected in a predetermined number in a collection device to form so-called bag stacks or bag packages. As a feeding device for instance a horizontally moving pin stacking conveyor can be used. This conveyor receives the separated bags on stacking pins. The bag stacks can be secured by wire brackets. For this purpose either the bag stack is lifted off the stacking pins of the pin stacking conveyor and impaled on the legs of the wire brackets with the now loosely superimposed bags, or the legs of the wire brackets are inserted in the hollow-groove recesses of the stacking pins of the pin stacking conveyor, and the bags stacks are removed by lifting the wire brackets with the bag stacks thereon. Subsequently the bag stack has to be secured by means of safety plates or rubber plugs attached to the legs of the bracket. As a rule this process is performed manually by an operator. Attempts have been made to perform automatically the bracket feeding and the bag pickup by the wire brackets. A transfer device of this type is known for instance from German patent document DE 38 34 115 C1.
German patent document 198 39 144 describes a robot-controlled multifunctional hand, which can be moved between a receiving position wherein it picks up a respective bag stack from the pin stacking conveyor and a discharge position, wherein an interlocked bag stack is deposited in a cardboard box or the like in a boxing station, thereby automatically introducing the bag stack into the cardboard box and simplifying and accelerating the packaging.
Independently of whether the introduction of the bag stack into the box is done manually or by means of a robot, the transport container corresponded basically to the size (length and width) of the bag stack. The bags introduced in layers into the cardboard box rest more or less with their lateral edges on the side walls of the cardboard enclosure. The wire brackets holding the bags together are turned over inwardly. The result of this inward flipping of the legs of the wire brackets are unilateral buildups or bilateral buildups when the bags are layered in a staggered mirror-image manner, with a depression in the middle of the stack. Since the individual bag stacks are sometimes also covered on both sides by paper strips or intermediate paper layers, and in addition the above mentioned rubber plugs are attached to the wire brackets, relatively high demands are made on the operator. This particularly then, when due to relatively high production speeds, the continuously repetitive motions have to be performed in short time spans.
It is an object of the invention to provide an improved method of packaging bag stacks whereby the handling of bag stacks, particularly the introduction, the removal, as well as optionally the supply and positioning of the bag stacks to an automated packing machine can be performed automatically with particularly simple means.
Another object is to provide an improved method of packaging stacks of plastic bags whereby drawbacks of earlier packaging systems are obviated.
It is also an object to provide cardboard which allows for a simple manipulation of the bag stacks introduced in the transport container.
These objects are achieved, in accordance with the invention, in that the bag stacks are introduced into the transport container with outwardly directed wire bracket legs and are removed for use from the transport container (usually a cardboard box) in a substantially unchanged position. The introduction of the bag stacks into the cardboard enclosure is controlled according to the invention so that the bag packages are laid into the transport container in layers arranged in a mirror-image manner. This permits not only an automated introduction, but also an automated removal of the bag packages, for instance by means of a handling device controlled by means of an optic device or by a robot system which recognizes the position of the wire brackets and grips them for seizing the bag pages, and for instance feeds them to a filling station, such as an automated packaging machine, and positions them in that machine.
Because of the introduction of the bag packages into the box with outwardly pointing wire bracket legs according to the invention, it is basically possible to eliminate the rubber plugs on the wire brackets, which otherwise would be required for securing the individual bags.
For the special kind of bag introduction merely a transport container (especially a cardboard enclosure or box) is required, which on the side of the wire brackets is longer than the bag packages by a distance which allows that the wire bracket legs passed through the suspension holes of the plastic bags to point essentially horizontally outwardly with respect to the side wall of the transport container.
With the means according to the invention an effective automation process can be used in the bag package removal from a transport container (cardboard box), with the positioning of the bag stacks on an automated packaging machine.